The prevalence of diabetes has lately been increasing markedly in the westernized world. As of 1980, diagnosed diabetes represented approximately 2.8% of the U.S. population, although the actual total number of diabetes in the U.S. thought to exceed ten million.
The most important factor for reducing diabetes-associated complications is the maintenance of a tight glucose control, i.e. euglycemia. The maintenance of euglycemia may prevent and even reverse many of the sequelae of diabetes.
Presently, patients can monitor either their urine glucose or blood glucose. Urine glucose testing is essentially qualitative and not quantitative because the results represent an average blood glucose and additionally are affected by the renal glucose threshold. In contrast, frequent home glucose monitoring has been shown to have an excellent correlation with 24 hour blood glucose levels. A regular daily schedule of glucose monitoring allows patients to titrate their insulin dosages thereby achieving good control. After obtaining a droplet of blood, the glucose concentration may be determined with either test strips or a glucose meter. The article "Diabetes, the Comprehensive Self-Management Handbook" printed by Doubleday and Company of Garden City, N.Y., 1984, discusses in detail the goals and problems of self-testing of blood glucose. The major problem is that many diabetic patients intensely dislike to attempt blood glucose monitoring because a finger stick device must be used to obtain a drop of blood. The article discusses the use of automatic devices which help make the finger stick procedure easier. One such device is the Autolet which automatically performs the finger stick maneuver, the device being made by Owen Mumford Limited of England. The Autolet works as a lancet is fitted into a spring loaded arm. The arm is pulled back against the spring and secured in place by a lock. The finger is placed against the platform of the device. A button is pushed to release the lancet which automatically pricks the finger. Autoclix made by Bio-Dynamics works on the same principle. The lancet is hidden from hand and is released upon the pressing down of a button. A third device is the Monojector Lancet device, manufactured by Monoject Company.
The U.S. Pat. No. 4,203,446 to Hofert et al discloses a precision spring lancet which is automatically retracted back into the device after piercing a patients skin. The U.S. Pat. No. 4,360,016 to Sarrine discloses a blood collecting device having a lancet and a capillary tube carried together in a tubular housing. This device relies on capillary action for the removal of blood from the incision. The Hofert et al patent requires milking of blood from the pierced finger to force blood out through the incision.
The aforementioned devices utilize the piercing of a finger as the finger tip is highly vacularized and it is possible for the patient to "milk" the drop of blood from the finger tip. However, pain receptors have a very high concentration on the finger tips as compared to the forearm, trunk, buttocks, and upper thighs. Repeated blood samplings from small areas such as the finger tip results in the formation of scar tissue. Although the aforementioned automatic devices represent an improvement, they are still limited to the finger tips. They cannot be used on other body parts as the other body parts are not highly vascularized. Also, there is no way of milking a drop of blood from those areas.
The instant invention provides a device which can obtain a blood droplet from areas other than the finger tip such as the forearm, thigh or abdomen. This is advantageous since there are fewer pain fibers as well as much larger areas to sample from which avoids the formation of scare tissue on the fingers. Moreover, the utility of this device would not be limited to diabetes. For instance, it could be used in lieu of a heal-stick on neonates or whenever a small blood sample is needed from a patient.